Coil winder (small volume)

George Herold wrote in news: snipped-for-privacy@googlegroups.com:

lots of good chinese units on ebay. The turns counter is the most important thing.

At a mere 100 turns, the coil builder can lay down the wire neatly without a spool reel attachment.

I had to make some of my own bobbin mounting cones for my larger form factor stuff.

most are 220V 50Hz tho, so you'd need a tranny.

The hand winders are likely all you'd need. They are cheap. same search on ebay.

coil winder

I need an air-coil winder too.

I've been winding these myself on a Sharpie pen.

Well I can send you a quote for those. :^) We need these at the moment.

The most important thing is for it to look nice... no scatter winding.

George H.

We wind some of our less precise ones on a lathe. Getting all the rows and layers to lie nice is not so easy.

George H.

it'll need some simple mechanical modifications to make it big enough for 10" coils but,

That's pretty heavy wire- AWG 18 (~1mm) according to the datasheet.

Straightening might be as much of an issue as tensioning.

--Spehro Pefhany

With an NC lathe it should be trivial. Just clamp the bobbin or form to a faceplate, and spool from the cross slide, with the usual friction and dekinking guide rollers. The carriage just has to move back and forth synchronized with the spindle motion, as though threading. If there's lots of layers, it helps to hand-wrap a tape layer between.

There was a coil-winder at the old lab, in the basement. When I used it, it took under an hour to do a batch of coils, then it collected dust for a few months... motor speed, counters, felt clamps, autoreverse, wire guides, all those things needed a few minutes of tinkering, but the actual winding was quick.

Wind on drill shanks - you get a rack of different sizes and can also use them for making holes :)

Clifford Heath

John Larkin wrote in news: snipped-for-privacy@4ax.com:

If you use a neutral material, you can leave the coil on the forming core.

Also, air core? That sounds like too much of a hassle to try to use a winder for. Better done by hand even if you use a winder to pull the wire.

Ideal spacing for air core is one wire diameter space between each turn.

George Herold wrote in news: snipped-for-privacy@googlegroups.com:

It depends on the wire gauge you are using. Fine wire is hard to work with and easy to pull too hard as well. And that precision, constant tension is important once you get into the finer gauges above say #30 gauge. After seeing your coils, I would say that you should get one of the more expensive models which include the precision transition device. Yours looks like about #43 and 195 turns on that span must be more than one layer. One way to get subsequent layers to lay flat and not fall into the previous layer is to place one turn of 1 mil transformer tape on each layer as you wind the last turn of that layer and that then transitions into the next layer and gives a flat base to wind it onto. I have wound a LOT of high turn count fine gauge wire coils, some with several 150 turn layers which MUST be segregated from previous layers due to volt per turn considerations and the insulative strength of transformer (magnet) wire. One does not want turn number 865 getting up close with turn number one. At just under 2 volts per turn, that still adds up to more than the 1500 volt average dielectric strength of the transformer wire.

Another thing you could do is encapsulate it in a clear resin such that polishing it after makes the coil look like it resides under

speff wrote in news: snipped-for-privacy@googlegroups.com:

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Now say #43 gauge... now THAT wire needs to be worried about in use.

I had 1500 turn secondaries at #54 gauge on a six segmented flatpak transformer. Those required vacuum encapsulation. That wire had to be pulled and wound *very* carefully.

Huh, OK, Thanks Spehro. I know basically nothing about coil winding. For the lathe winding we take wire off the large spool it comes on... ~1 foot diameter in ~50 lb spools.. (I'd have to check both those numbers.)

In commercial coil winders, is there some wire straightening/ pulling stage? Oh, Right 18 AWG.

George H.

So maybe a coil winding machine is what we need.

Are there any 'name brands' I should look for? (The Bridgeport (Mill) of old coil winders.)

George H.

Well the coils I pictured are 18 AWG, 13 layers, 15 rows/layer...

I think there's like 400 turns on the laser diode coils... I wanted to get to 100 Gauss... with decent homogeneity over a ~1" cubed sample size.

George H.

yes, a set of alternating up/down rollers de-curl the wire

one image that cought my eye:

That's adjusted until the wire comes out dead straight that way you know that when wound the turns will lie flat next to each other.

I found this article interesting:

BTW that site is not on the internet archive due to robots.txt - so may be worth backing up if you like it...

Thanks I'll give it a read...

George H.

I was in charge of a Eubanks 2700 wire cutting and stripping machine once that had two sections like that, at right angles. That way the coil orientation relative to the straightener didn't matter. Adjust the roller spacing so the wire it bent back and forth "some but not too much" :-). Too much just causes extra drag.